1. Field of the Inventions
The present inventions relate to boats having boat propulsion units, such as outboard motors, and more specifically to control of boat propulsion units in accordance with control signals transmitted by an onboard device or devices.
2. Description of the Related Art
Outboard motors mounted on the outside of boats are used for providing propulsion and steering functions for boats. In recent years, onboard LAN systems have been developed to replace outboard motors' throttle control mechanism operated via the cables installed onboard. An example of such a system is disclosed in Japanese Patent Document JP-A-2003-146293. The onboard LAN system connects the outboard motor and the hull by means of a LAN (Local Area Network), and controls the outboard motor by control signals transmitted by an onboard device. The onboard LAN system allows connection of many devices to one cable, simplifying the wiring between the hull and the outboard motor. A PTT (Power Trim and Tilt) switch is also connected to the onboard LAN to control the trim and tilt angles of the outboard motor.